Wednesday, January 20, 2010

IPCC statement on the melting of Himalayan glaciers1

The Synthesis Report, the concluding document of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (page 49) stated: "Climate change is expected to exacerbate current stresses on water resources from population growth and economic and land-use change, including urbanisation. On a regional scale, mountain snow pack, glaciers and small ice caps play a crucial role in freshwater availability. Widespread mass losses from glaciers and reductions in snow cover over recent decades are projected to accelerate throughout the 21st century, reducing water availability, hydropower potential, and changing seasonality of flows in regions supplied by meltwater from major mountain ranges (e.g. Hindu-Kush, Himalaya, Andes), where more than one-sixth of the world population currently lives."

This conclusion is robust, appropriate, and entirely consistent with the underlying science and the broader IPCC assessment.

It has, however, recently come to our attention that a paragraph in the 938-page Working Group II contribution to the underlying assessment2 refers to poorly substantiated estimates of rate of recession and date for the disappearance of Himalayan glaciers. In drafting the paragraph in question, the clear and well-established standards of evidence, required by the IPCC procedures, were not applied properly.

The Chair, Vice-Chairs, and Co-chairs of the IPCC regret the poor application of well-established IPCC procedures in this instance. This episode demonstrates that the quality of the assessment depends on absolute adherence to the IPCC standards, including thorough review of "the quality and validity of each source before incorporating results from the source into an IPCC Report" 3. We reaffirm our strong commitment to ensuring this level of performance.

1This statement is from the Chair and Vice-Chairs of the IPCC, and the Co-Chairs of the IPCC Working Groups.

2The text in question is the second paragraph in section 10.6.2 of the Working Group II contribution and a repeat of part of the paragraph in Box TS.6. of the Working Group II Technical Summary of the IPCC Fourth Assessment Report.

3This is verbatim text from Annex 2 of Appendix A to the Principles Governing IPCC Work.